The present invention relates generally to training simulators and, more particular, to a method of accessing and displaying image data for use with
Simulators, such as aircraft flight trainers, and the like, are currently in wide use. The simulators are used to train vehicle operators, both military and commercial, or to permit an operator to become accustomed to the terrain over which he is to maneuver.
A major subsystem of mary simulators is a computer image generator (CIG). This device generates a realtime two-dimensional CRT image of the terrain over which the simulated vehicle is moving. The images which may be displayed include visual, infrared, or radar images, or the like. As is typically the case, a large data storage unit, such as a magnetic rotating disc memory, is utilized to store digital data indicative of images representing the terrain which is to be displayed. A person utilizing the simulator sits in a cockpit, for example, and "flies" the simulator as he would a conventional aircraft. The various aircraft flight controls interface with signal processing circuitry which accordingly control the images that are projected to the pilot.
Conventional systems have run into problems in dealing with the rapid update of displayed data. For example, if the simulated vehicle is made to traverse over the crest of a hill, the previously non-visible terrain image on the other side of the hill must be quickly accessed and projected to the operator in a very short time. Conventional CIG's have employed very coarse memory management schemes in which the data base is divided into segments corresponding to relatively large geographic areas. As the simulated aircraft moves from one area to another, the corresponding segment is read into memory. For a practical main memory size and for the large geographical area covered by each segment, the achievable scene detail has been severely limited. Furthermore, conventional CIG's serial data processing schemes which limit the speed at which data can be retrieved from the data base and displayed to the operator. The display may become blurred or the image may be discontinuous or jumpy, depending upon the system. This problem also has severely limited the scene detail that could be achieved for the situation just described.
Therefore, it would be an improvement to the CIG art to provide for a method which would allow for the rapid update of displayed images in situations where the terrain changes abruptly. This is particularly important for helicopter simulators.